The authors investigate the impact of partner brands’ salient personality on brand alliance success in a hospitality context. Hospitality brands often collab¬orate with brands with a complementary personality to enrich their image or brands with a similar personality to deepen their image (pilot study). But our two experiments using both real and fictitious brands indicate that a brand alliance between partners of complementary personality can dilute their salient personality attributes (Study 1) and consumers are less willing to engage in word-of-mouth behavior (Study 2). Personality similarity results in higher perceived fit and greater word-of-mouth intentions, but not necessarily more positive attitudes toward the brand alliance or each partner brand (Study 2). The authors also find that brand alliances have a more positive spillover effect on consumer attitudes and behavioral intentions toward sincere brands than ex¬citing brands while brand alliances between exciting brands are more likely to create buzz and perceived to have the highest fit. Implications for theory and practice are discussed.